Stencil sheet



July 2.0, 1937. J, ALPERT 2,087,564

S'TENCIL SHEET I Filed Aug. 26, 1.936

JUIN" IW g lfm

HU i? Patented July 20, 1937 1 Claim.

This invention relates to stencil sheets of the type adapted to be prepared for use on a typewriter and then Used for reproduction purposes on a stenciling machine having means for applying ink through the stencil sheet upon cards or paper etc.

Such stencil sheets are provided ordinarily with a relatively stiff but flexible backing sheet provided with holes at one or both ends for attachment to the drum of a duplicating machine.

For actual use of the stencil the main part of the backing sheet is to be detached for exposing the stencil sheet proper, which, however, remains permanently connected with one or both end strips of the backing sheet for better attachment to the drum of the duplicating machine. Said main part of the backing sheet being of slightly shorter length than the stencil proper is not adapted to any further useful purpose Wherefrorn a considerable wasting of valuable material results.

'I'he invention is to avoid this waste by adapting said main part to replace the somewhat eX- pensive exible protective covers which usually in duplicators are placed on the outside of the pad on the cylinder after removing the stencil for preventing leakage of ink and keeping the pad moist and clean. It has been found that the somewhat hygroscopic strong material of the backing sheet is very suitable for these latter purposes.

In the accompanying drawing which illustrates the invention,-

Fig. 1 is a top view of a stencil sheet as supplied to the trade;

Fig. 2 is a perspective View of a sheet in the form in which it is applied to the typewriter;

Fig. 3 is a top View of the sheet in the form when ready to be applied to the stencil machine, a portion being broken away;

Fig. i is a top view of the detached main part of the backing sheet.

'I'he particular embodiment of the invention chosen for the purposes of illustration comprises the stencil sheet S and a backiing comprising the end portion E and the main portion I. The stencil sheet may be of any suitable construction adapted to permit the passage of ink through the portion struck by typewriter keys without permitting the passage of ink through the remaining portions. The backing is relatively stiff but exible, and it should be adapted to absorb moisture to some extent. The backing projects beyond the ends of the stencil sheet S and the projecting ends are provided with openings O (C1. Llla-3.5)

adapted to hook over lugs on the stencil machine to hold the sheet in position. The stencil sheet is hooked on the stenciling machine at one end, whereas the other end ordinarily is received in a clamp of the machine.

The stencil sheet S is fastened to the backing along one end margin preferably by cement as indicated at M in the gures. The backing is weakened along the line L inside the cemented margin so that the end E may be separated from the main portion I.

The preferred method of using the stencil sheet is as follows: The sheet S is swung away from the main portion I as shown in Fig. 2, so that the portion I may be moistened if desired. After the backing has been moistened the stencil sheet is swung back into contact therewith and is then applied to the typewriter. The end of the stencil connected with the backing sheet (the left-hand end in Fig. 2), is preferably inserted foremost in the typewriter, inasmuch as the sheet will feed through the typewriter better in this direction. After the typing operation the main portion I of the backing is separated from the end E along the line L. This leaves the stencil in the form shown in Fig. 3. The sheet is then ready to use in the stenciling machine, and the attaching means preferably applies a yielding tension to the sheet, so as to hold it flat in the stenciling operation.

Attention is called to the fact that the distance d between the engagement ends of the holes O in the strip E and the free (right hand) end of the stencil sheet S is the same as the distance between the engagement end of the holes in the main part I of the backing sheet and the free end of the latter (Fig. 4) or the perforation L (Fig. l). Consequently the main part I oi the backing can be attached to the drum of the corresponding duplicator as a substitute for the usual flexible protective cover after removing the stencil. The increased length of the main part of the backing sheet also enables it tc be used as a very convenient preserving means for filing the stencil after use. For this purpose until now it is customary to use newspaper or other makeshift means having neither the strength nor the preserving hygroscopic character of the backing material. rI'hereby a further material advantage is obtained.

Stencils are kno-wn with backing sheets projecting at both ends, however, there the stencil sheet proper is secured permanently at both ends to the backing sheet, and the detachable main part of the latter is shorter than necessary for attachment to a duplicator drum corresponding to the size of the stencil. YThe advantages and purposes of the present invention, Vthereforerare not obtainable by the use of such earlier stencils.

I claim: l

A stencil Comprising a stencil sheet and a backing thereforesaid sheet being attached to the backing at but one end of said sheet but being free of the backing at the other end, the

backing extending beyond said other end of said sheet and having at both ends rows of holes and having a weakened line inward of said attached end, the distance between the row of holes in the attached end of the backing and the free end of the stenciI being equal to the distance between the row of holes in the free end of the backing and the weakened line.

JERRY ALPERT. 

